In the example described in document FR-2,811,395, this type of vehicle comprises a gearbox with a motive primary line arranged substantially parallel to a receiving secondary line that controls the drive wheels of this vehicle. The primary line consists, on the one hand, of a principal driving shaft driven in rotation by the thermal engine through a disengageable coupling and, on the other hand, of a tubular auxiliary driving shaft driven in rotation by the electric motor and surrounding the principal driving shaft. The principal driving shaft and the auxiliary driving shaft can be rotatingly connected to one another by a claw. Each one of these shafts fixedly carries two gear wheels in mesh with receiving gear wheels carried by the receiving secondary line and mounted rotatingly loose on this line. This line also carries alternate-clearance sliding gears allowing the receiving gear wheels to be rotatingly secured to this secondary line.
Thus, during operation, the vehicle is powered at different speeds either by the electric motor or by the thermal engine, or by both. This is achieved by acting upon the various couplings (disengageable coupling and/or claw and/or sliding gears) carried by the various lines in order to secure the principal driving shaft with the thermal engine and/or this principal driving shaft with the auxiliary driving shaft and/or one of the receiving gear wheels with the receiving secondary line.
Although this transmission device is satisfactory, it however involves quite significant drawbacks.
Indeed, when only the electric motor is used for powering the vehicle, coupling the receiving wheel with the secondary line is necessary so as to transmit the rotating motion of this electric motor to this secondary line. This therefore requires a complication of this device to fulfil a basic function.
Furthermore, the vehicle must comprise a multiplicity of actuators for controlling the disengageable coupling, the claw and the sliding gears. These actuators increase the production cost of the device and can lead to failure and/or dysfunction.
Besides, these actuators must be controlled by a processing unit such as the calculator the engine is usually equipped with, which requires increasing the capacity of this calculator.
Finally, it is necessary, in order to obtain the desired speed, to couple or to uncouple some elements of the device, such as the receiving gear wheels. This increases the time required for shifting gears while causing driving discomfort.
In order to overcome these drawbacks, as better described in document FR-2,962,379, the applicant has developed a powertrain for driving a hybrid type vehicle comprising a gearbox with a motive primary line arranged substantially parallel to a receiving secondary line that controls the drive wheels of this vehicle. The primary line consists of a driving shaft driven in rotation by the thermal engine through a disengageable coupling. The driving shaft fixedly carries two gear wheels in mesh with receiving gear wheels carried by the receiving secondary line and mounted rotatingly loose on this line with one of these wheels carried by the secondary line through a one-way coupling.
The applicant has continued improving this powertrain by combining the simplicity of a gearbox and the ease of use thereof with a longer vehicle running time in electric drive mode.